Sex-segregated personal facilities exist because there are some very particular ways in which men and women remain different, and always will be different. We need not go into detail to observe that men and women have different experiences in restrooms, locker rooms, and other sex-segregated places because of the differences in their anatomy. Separating the sexes in these facilities allows for distinct physical accommodations proper to the needs of men and women, but more importantly it allows for camaraderie among those who share the whole life experience of manhood or womanhood—among those who are the same. Advice, help, humor—there are some things that only those of the same sex can fully understand and appreciate, and which would not only be awkward but senseless to discuss with someone of the opposite sex (other than, perhaps, a spouse). Secondarily, these personal facilities also implicate parts of the body that are particularly sexual in nature, even if nudity is not present. Personal facilities are sex-segregated in order to reduce their sexual nature. Healthy and professional non-sexual relationships between men and women depend on banishing the specter of sexuality from public facilities—even placing to one side the threat of harassment and general boorishness.

As Think Progress explains:

McGinley’s argument requires the assumption that everybody in the locker room presents as the same gender and is attracted to the same (opposite) gender, thereby erasing not only transgender people, but all LGBT people.

We won’t be made invisible anymore. And we won’t let them erase our transgender friends, family and loved ones, either.